The present invention relates to lamps of the type commonly used for outdoor area lighting and known alternatively as quartz lamps or halogen lamps.
Quartz lamps are often used for area lighting because they can provide considerable light over a comparatively wide area more efficiently than an incandescent lamp. The lamps are called "quartz" lamps because they contain a bulb that typically has a quartz or equivalent fused silica envelope. The envelope contains a halogen gas as an active agent for emitting the light. The envelope is slender, typically about four inches (ten centimeters) long, and has metallic electrical contacts on both ends. In known quartz lamps the bulb is commonly held in place by inserting the ends into bulb holder/contacts, which may include spring-biased mounts or bayonet mounts or other types of mounts for holding the bulb in place and for assuring good electrical contact with electrical leads in the lamp housing. The lamp housing typically contains a reflector positioned behind the bulb and a transparent, typically glass, window positioned in front of the reflector and bulb.
With quartz lamps of the past it is awkward to change the halogen bulb. In known designs it is typically necessary to open up the lamp housing and remove the glass window to gain access to the bulb within the housing. Thus, prior quartz lamp housings have typically been formed of separable halves or formed with a large window that could be removed and that provided sufficient room for the user to reach in and grasp the bulb. An expired bulb may then be removed by reaching into the housing and twisting or otherwise manipulating the bulb until it pops out of its holder/contacts. A new replacement bulb is then inserted by a similar manipulation, and the housing and glass window are re-assembled. Changing the bulb in this manner presents a number of inconveniences and hazards. The working conditions are not always the best because the lamp is often mounted in an inconvenient location. The lamps are typically mounted high on the wall of a building or under a soffit, or they may be mounted high on a post or on a low support, for example, by a pathway. In any event, the lamp is not usually mounted in a convenient position for disassembling and for manipulating the bulb inside. It is not uncommon to need a ladder to gain access to the lamp for replacing the bulb. In addition to the grace and dexterity required to change the bulb under these circumstances, there is a potential hazard from the edges of the glass window, which are typically sharp enough to cut the user if not handled carefully during the disassembly and replacement. And there is always the possibility of dropping the glass window and breaking it while replacing the bulb. There is the further hazard of electrical shock if the power has not been turned off, because the interior of the lamp housing and the live electrical contacts may be exposed. Furthermore, it is desirable to handle the envelope of a new halogen bulb as little as possible because residues left on the envelope from finger oils can lead to premature failure of the bulb. However, in the conventional method of changing a halogen bulb, some handling of the envelope of the bulb has been unavoidable when the two ends are inserted into their respective bulb holders/contacts.